It seemed important to John and I that we visit this refuge, and that turned out to be a good idea because it is this refuge that has made possible some of the other parks which we have visited in our travels. I will explain that further as I describe what the mission is of this place. It was established in 1936 by executive order of Franklin D. Roosevelt, and is our nation's only national wildlife refuge established to support wildlife research. The refuge and adjacent federal lands comprise the largest green space in the Washington D.C.- Baltimore corridor. Since its beginning it has been in the forefront of research in environmental contamination and endangered species research as well as migratory bird conservation. Our first stop in the refuge was at the visitor's center, which has wonderful displays explaining the past research as well as what is being done currently. In the 1960s when certain birds as the whooping cranes, bald eagles and condors started disappearing this wildlife refuge began research into the use of DDT. It was discovered that the sprayed accumulation of such pollutants affected earthworms, they received as much as 100x pesticide as was applied to the soil. Following other clues the research center learned that pesticides thinned the egg shells of birds and consequently stressed bird populations. It is at this center that whooping cranes have been propagated and reintroduced back into the wild. A couple of years ago John and I visited Aransas Wildlife Refuge in Texas and were privileged there to see several whooping cranes. Another species which have become endangered has been canvasback ducks- the refuge here has also worked at restoring their populations. That duck is another bird which John and I were fortunate to see when we were in Texas. Too some extent it was a bit depressing to learn at the center how we have so badly messed up our planet. However, I am thankful that our government has research areas as Patuxent where some species are being brought back from extinction. We spent way more time than we had planned to at the visitor's center, and it was late afternoon before we began hiking the trails of the refuge.